Sound transmitting and receiving diaphragm



Jan. 31, 1928. v 1,657,570

} H. FISCHER SOUND TRANSMITTING AND RECEIVING DIAPHRAGM Original Filed Jan. 1 2

' VENTEJR Ham 1' FISCHER EYM/ai Patented Jan. 551, i928.

rarest nnnraann rrsonnn, or new YORK, 1v. Y.

SOUND SMITTING AND RECEIVING DIAEHRAGM.

Application filed'January 14, 1925, Serial No. 2,247. Renewed November 23, 1927.

This invention relates to an improvement in sounddiaphragms for the transmission, .reception,reproduction or amplificat on of sound waves, and whether the transmission, reception or reproduction is by telephone, radiophone or other mechanism. 1

In the various devices for transmitting or reproducing sound waves, a diaphragm is employed which is customarily iron, because of the ready action thereon of the magnetic high tones are of high vibration and greater force. The object of the present invention is to provide a diaphragm which is adapted for both the high and the low tones of the scale and which will reproduce; both tones without distortion. i

The invention will be understood by reference to the accompanying drawings in which- Figure l representsa diaphragm provided with a central disk member, an annular rim and two legs orwebs connecting the rim to the central member; V

Figure 2 is a cross-section of a diaphragm, the section being atits axis (as along the dotted line 2, Figure 1),the construction being thesame as in Figure 1 with the eX- ception that the web is ofuniform width and is connected by an eyeletti to the disk 5.

Figure 3 represents a modification of Fig ure 1 in that the number of the connecting legs are increased; Figure 4 represents a further modification of the structure illustrated in Figure 1.

Unlike the usual sound receiving or transsuch as iron, connected by the legs or .webs 3 to an annular rim 1. This said structure is superposed upon and preferably firmly united with a disk 5 which may be of nonmagnetic material if desired, or material weakly responsive to magnetic waves, as for example duralumin, aluminum, or fibre. In some cases paper stiffened with shellac cr othersuitable stiffening agent may be employed.

\Vhcn the disk 5 is made of a metal, as for, example aluminum, it is preferable that its thickness be about .001 m. m. or .002 m. m., the iron part of the diaphragm about .009 m. m., although the thickness of the diaphragm members may vary somewhat from these figures without greatly afiecting their action. T

In connecting the disk 5 to the iron member of the diaphragm, I may, in addition'to or in substitution of welding or cementing, employ a mechanical connectingdeviee such as the flanged eyelet 6 shown in the cross sectional view, Figure 2.

The modifications of my device as illustrated in Figure 1, embody the same principle, but those shown in Figures 3 and L employ greater areas of the magnetic diaphragm unit. In all cases the high tones are satisfactorily transmitted by the relatively stiff magnetic iron unit, and vibrations of the lower tones are carried to the softer, less resistant member of the diaphragm and are satisfactorily transmitted thereby without 7 distortion.

. The annular rim 4 oi the magnetic unit of the diaphragm is not essential from the standpoint of operation, but aflords a ready means of permitting the diaphragm to be clamped in position in exactly the same manner as the diaphragm now in use.

It will be understoodthat I have illustrated in the drawings several only of many possible forms of my. diaphragm and that those shown in the drawing are illustrative .ofthe principle of my invention, what I claim and desire to secure by Letters Patent being as follows: I

1. A sound diaphragm comprising a'disklike member of magnetic material formed with its central area connected to its periphy by spaced webs, and a second disk-like .=..Le1r.ber iess resistant to sound waves and applied to the face 'of the first member and closing the spaces between the webs thereof. 2. A sound diaphragm comprising a disk of magnetic material having a central area -connected to itsperiphery byspaced webs, and a second disk less resistant to sound waves applied directly to the face of the first disk and co-extensive therewith, the arrangement being suchthat the peripheries of both disks may be clamped in position by the .10 same means when the diaphragm is employed in a' casing.

In testimony. whereof; I have name to this specification;

HERMANN FISCHER.

signed my 

